1. Field of the Invention
This invention relates to a product for soil stabilizing, made up of a prepolymer with terminal isocyanate groups, obtained by reaction of a polyol with a stoichiometric excess of polyisocyanate.
2. The Description of the Prior Art
Various products for stabilizing soils are already on the market.
These products are used as a solution or emulsion.
However, many of these soil stabilizers present disadvantageous side properties, such as phytotoxicity, lack of biodegradability and the like.
Other soil stabilizers are difficult to use in practice. This is for example the case with soil stabilizers known from British Pat. No. 1,322,490.
This British patent concerns soil stabilizers based on urethane prepolymers to which water has to be added in order to form polyurea polymers which can then be spread on the soil.
Such prepolymers can be represented as follows: EQU O.dbd.C.dbd.N--R.sub.1 --N.dbd.C.dbd.O
wherein R is a polyalkylene oxide chain with a minimum of 70% of ethylene oxide.
In the presence of water, the prepolymer is transformed into a polyurea polymer according to following reactions: ##STR1##
Such prepolymers are of a hydrophile character in order to ensure their solubility in water, with the consequence, however, that when diluted with water, the formed polymers gel after a few minutes. Due to the fact that such agar-like gels are no longer usable, it is necessary in order to be able to apply such stabilizers on the soil, to use a sophisticated two-component apparatus which precisely meters prepolymer and water, mixes them and immediately spread them on the soil.
Another drawback of these known prepolymers of high ethylene oxide content is their relatively high solidification point so that it is necessary in most cases to use diluent agents in order to maintain the prepolymer in a liquid state at normal temperatures of use.
Another drawback is also that such gelled polyurea polymers have low adhesion properties, which does not facilitate formation of aggregates of the soil particles to be stabilized.